1. Field of the Invention
This invention relates to a method and apparatus for the near simultaneous determination of sulfur and nitrogen in a sample material by a chemiluminescence detection and quantification technique.
More particularly, the present invention relates to a method and apparatus for the determination of nitrogen and sulfur in a sample material by oxidizing the sample material to generate nitrogen and sulfur oxides followed by reducing a portion of the sulfur oxides generating sulfur species capable of ozone induced chemiluminescence, while not reducing the nitrogen oxide species capable of ozone induced chemiluminescence, contacting the nitrogen and sulfur species with ozone to produce nitrogen chemiluminescent light and sulfur chemiluminescent light which lights are independently and substantially simultaneously detected and quantified.
2. Description of the Related Art
U.S. Pat. No. 4,018,562, now Re. 34,668 discloses a chemiluminescence technique for detecting and quantifying of nitrogen within a sample material. The sample material is first oxidized to convert the nitrogen in the sample into nitrogen oxides including nitric oxide. The nitric oxide is reacted with ozone to produce a chemiluminescent reaction. The emitted light energy is then detected in the 600-900 nanometer region of the electromagnetic spectrum. The intensity of this emitted light correlates to the quantity of nitrogen present in the original sample and measurement of this light by a photomultiplier tube or photodiode and associated circuitry permits one to quantify the amount of nitrogen present in the original sample.
U.S. Pat. No. 4,352,779 discloses a chemiluminescence techniques for detecting and quantifying sulfur within a sample. The sample material is first oxidized to convert the sulfur into oxides of sulfur. The oxides of sulfur are then subjected to a chemical reduction resulting in the formation of hydrogen sulfide that is reacted with ozone to produce a chemiluminescent reaction. The emitted light energy is then detected in the 300-500 nanometer region of the electromagnetic spectrum. The intensity of this emitted light or photoemission is measured by a photomultiplier tube or photodiode and associated circuitry generates a signal that correlates to the quantity of sulfur in the original sample.
Currently, chemiluminescence techniques are one of the most sensitive techniques with wide dynamic range for detecting and quantitating the concentration of nitrogen and/or sulfur in a sample material. These chemiluminescence devices are, however, nitrogen or sulfur specific and simultaneous determination of both sulfur and nitrogen require a dual analysis technique, i.e., the sample material is split into separate two fractions for separate nitrogen and sulfur detection. Sample fractionation procedures do not assure that each fraction has exactly the same composition. Moreover, if the sample to be analyzed is a chromatographically separated component of a more complex mixture of chemical components, the separated component may represent a very small amount of material making fractionation difficult and often times problematic. Thus, it would be an advancement in the art to have an apparatus and a method for near simultaneous detection of the concentration of nitrogen and sulfur in a sample by ozone induced chemiluminescence.